The painting machine
Aarons studio is in a modern purpose-built block on the UCSD campus in La Jolla. Canvases are stacked ten- or 12-deep, others fill the racks at the back of the room. It could be any artists studio any
Aarons studio is in a modern purpose-built block on the UCSD campus in La Jolla. Canvases are stacked ten- or 12-deep, others fill the racks at the back of the room. It could be any artists studio anywhere, except for a few incongruities - a soldering iron, a couple of PCs, a scattering of screws and circuit boards, and the large machine at one end of the room. This is Aarons easel - a horizontal vacuum table the size of a double bed. Above it is a robot arm attached to a travelling gantry - rather like a large XY plotter.
Harold Cohens assistant, Matthew, measures a large sheet of art paper and lays it out on the vacuum bed, fixing it with masking tape round the edges. The two of them bustle round one end of the machine where a row of 16 paint bottles and seven brushes has to be prepared. Once everything is ready and the computer has been given the dimensions of the paper, the robot arm picks up a small pot and fills it with black paint from one of the bottles. It selects a brush (actually, more like a broad felt-tip pen), dips it into the pot and begins to draw.
Initially, theres no apparent logic to its efforts - a short line here, a longer one there. Occasionally, it scoots off to the far edge of the paper and places a single dot - the result, Cohen thinks, of some minor bug in the code. The program works from front to back rather than completing any object or area before moving on. Watching the evolving picture, Im reminded of the question that originally drove Harold Cohen into AI: What is it that makes some marks on a surface signify, while others dont? Suddenly, as the machine adds a short line to complete one closed shape. I see an eye and the meaningless arrangement immediately begins to develop into a face.
Aaron isnt actually present throughout all this. He demands something more sophisticated than the paint-spattered old PC which drives the painting machine. Instead, the instructions for this picture have all been downloaded onto a Zip drive and carried to the studio. Anyway, the creative part is over now, and whats left is a process of control engineering to convert Aarons imagined picture into precise movements of the servos. The technology is impressive. Even though it has a slightly Heath-Robinson look - and makes a fearsome noise with its vacuum pump and many motors - the robot arm moves quickly and never drips any paint. Lines meet exactly as they should. When the drawing is finished, it carefully washes the brush in clean water and puts it back in its holder.
This article appeared in the April, 2000 issue of PC Authority.
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